Pheidole in the New World. A dominant, hyperdiverse ant genus. Author Wilson, E. O. text 2003 Harvard University Press Cambridge, MA http://atbi.biosci.ohio-state.edu/HymOnline/reference-full.html?id=20017 book 20017 Pheidole arboricola new species Types INBio. etymology L arboricola , tree-dwelling, alluding to the arboricolous nests of the species. Diagnosis A very small species, close to amazonica , mackayi , minutula , and especially quercicola , distinguished in the major from these species by its subangulate (as opposed to lobate) humerus in dorsal-oblique view, rounded lateral borders of the postpetiole, and bicolorous head. Measurements (mm) Holotype major: HW 0.76, HL 0.84, SL 0.40, EL 0.06, PW 0.40. Paratype minor: HW 0.42, HL 0.46, SL 0.40, EL 0.06, PW 0.26. color Major: head capsule anterior to eyes, along with a fuzzy circular spot in the middle of the capsule dorsum, light brown. Waist and gaster also light brown; rest of body and appendages dark yellow. Minor: body medium brown, tarsi yellow, rest of appendages light brown. Range Atlantic lowlands of Costa Rica, up to 500 meters elevation. Biology John T. Longino (1997) reports arboricola as a resident of moist mature and second-growth forest, nesting in the hollow branches and under the dead bark variously of Bauhinia, Cecropia, Stryphnodendron, and other trees. Figure Upper: holotype, major. Lower: paratype, minor. COSTA RICA: La Selva Biological Station, near Puerto Viejo (J. T. Longino). Scale bars = 1 mm.